This invention relates generally to crest gates for dam spillways and deals more particularly with a rigid gate pivotably provided at the top of the fixed spillway structure, which rigid gate is movable to a raised position by means of an inflatable bladder.
The provision of movable gates at the crest of a conventional dam spillway generally takes the form of an operating gate that may be either a rigid gate structure hydraulically raised or lowered to vary the height or head of the water, or in accordance with more recent technology, such a gate may take the form of an inflatable tube anchored at either end to a foundation so that the tube itself creates a head of water when filled with air or water and so that release of the air or water from the tube lowers the crest gate.